Merely guessing here, but they may be SNS casting hardcast 220gr. bullets. I have a number of these but I've never shot any out of the stock bbl and they're not gas checked either. I can't imagine they would lead terribly, but would expect them to lead some.

Underwoods TMJ 200 and 220 Hardcast are both "out of stock" I'll hold out for re-supply instead of buying DT's overpriced/underpowered offering. Until then my best bear round is the Underwood XTP sadly.

Wanted to get some chronograph results and see how the Underwood 220gr hard cast works in a Glock 29.

I decided to compare the spread of hits of the 220gr HC between my 1911 with its Bar-Sto barrel and my third generation Glock 29. The G29 is standard, except for a metal recoil rod assembly with a standard 17lb recoil spring.

I placed the target at 30 yards and shot slow strings with my hands resting on a shooting bag. Took lots of time to make sure my sights were aligned consistently. Each square on the target is 1x1". The group in the upper left is from the Glock. The better centered group is from the 1911. Proves in my mind that the Glock barrel does stabilize the 220gr ammo. Then I shot the Glock at a distinguishable formation on a berm about 60 yards away, standing off-hand. The hits were comfortably close to the target, showing again, the bullets stabilize.

I just received my new shipment from Underwood including a box of 220 grain hardcast. I love Underwood's speedy shipping and customer service. Ordered on Sat. And received them on Tues. The 220 grain loads will be my new woods carry round.

Underwood uses a 24# spring...he told me. He shoots hot all the time, so I'd imagine. I use a 22# SS rod/spring. Works great in both worlds.
Enjoy!

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DT does as well. It gives a few more FPS as the extra weight delays the unlocking a fraction of a fraction of a second. When I shot alot of hot 10mm I found 21# (G29) and 22# (G20) were plenty for the most powerful loads. The 24# G20 and 23# G29 springs returned diminishing results in my experience. Lighter springs really do result in less recoil, especially muzzle flip but more frame battering. There is more battering when slide go's back to battery with heavier springs though. If stock is 17-18#, a 22# spring is 20-25% heavier. Plenty for two well-designed pistols with very heavy slides by any standards.

DT does as well. It gives a few more FPS as the extra weight delays the unlocking a fraction of a fraction of a second. When I shot alot of hot 10mm I found 21# (G29) and 22# (G20) were plenty for the most powerful loads. The 24# G20 and 23# G29 springs returned diminishing results in my experience. Lighter springs really do result in less recoil, especially muzzle flip but more frame battering. There is more battering when slide go's back to battery with heavier springs though. If stock is 17-18#, a 22# spring is 20-25% heavier. Plenty for two well-designed pistols with very heavy slides by any standards.

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Spot on, I agree. A little increase in spring weight is appropriate but nothing overkill.

I use a 20lb spring for NUCLEAR loads in my 6" Fusion and had a 20-22lb spring in my G20 and they are or were both perfect.

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